添加面试题 02.07. 链表相交 javaScript版本

problems/面试题02.07.链表相交.md

@@ -155,6 +155,42 @@ Python：
 
 Go：
 
+javaScript: 
+
+```js
+/**
+ * @param {ListNode} headA
+ * @param {ListNode} headB
+ * @return {ListNode}
+ */
+var getListLen = function(head) {
+    let len = 0, cur = head;
+    while(cur) {
+       len++;
+       cur = cur.next;
+    }
+    return len;
+} 
+var getIntersectionNode = function(headA, headB) {
+    let curA = headA,curB = headB, 
+        lenA = getListLen(headA),
+        lenB = getListLen(headB);
+    if(lenA < lenB) {
+        [curA, curB] = [curB, curA];
+        [lenA, lenB] = [lenB, lenA];
+    }
+    let i = lenA - lenB;
+    while(i-- > 0) {
+        curA = curA.next
+    }
+    while(curA && curA !== curB) {
+        curA = curA.next;
+        curB = curB.next;
+    }
+    return curA;
+};
+```
+